Sauna increases number of muscle capillaries?

Passive heat treatment (such as sauna) has several health benefits, including lowering the risk of cardiovascular disease and all-cause mortality. But can it also improve muscle metabolism?

In our new study, we investigated whether 8 weeks of infrared sauna sessions (45 minutes, 3 times per week) in healthy older males and females could enhance:

• muscle fiber capillarization (amount of small blood vessels in muscle)
• microvascular perfusion (blood flow through small blood vessels)
• muscle protein synthesis (adaptation of muscle tissue)

Key findings:

• Muscle fiber capillarization increased by 37%
• No improvement in microvascular perfusion and muscle protein synthesis
• Improvement in overall health markers, including blood pressure and blood sugar response to a meal

What does this mean?

Our study suggests that repeated heat exposure can promote muscle adaptations. Exercise training remains the most potent stimulus for muscle adaptations. But passive heat treatment may be an interesting tool for individuals who cannot or do not want to exercise, such as heart patients.  

Sauna use is also popular among athletes. However, whether sauna use can further improve muscle adaptations in a trained population remains to be established.

Link to our study:
Fuchs et al. Repeated passive heat treatment increases muscle tissue capillarization, but does not affect postprandial muscle protein synthesis rates in healthy older adults. J Physiol, 2024

Go to the next uncategorized infographic:
More muscle, more capillaries?